Belt centering device



March'26, 1940. J. s. WOOD BELT CENTERING DEVICE Filed April 14, 1957 2 Sheefs-Sheet -1 N D, T 2 W NWQW.

March26, 1940. J. 5. W000 BELT CENTERING DEVICE 2 Sheets-Sheet 2 f Filed April 14, 1937 //VVE/Y7'OR-' JOHN S. WOOD,

BY 0 M Patented Mar. 26, 1940 BELT CENTERING DEVICE John S. -Wood, Huntington, WV. Va., assignor to r The Jeffrey Manufacturing Company, a corporation' 'of' Ohio Application April 14, 1937; Serial No. 136,839

11 Claims.

-This invention relates; toa beltcentering de- -vice for aconveyor.

An'objectof-theinvention is to provide a belt conveyor with a belt centeringdevice which is operative to maintain the belt in proper alignment regardless of the direction of travel of said belt. Y

- Another objectof'the invention is to provide a 'belt centering oraligning device which will maintam a belt in proper'alignment regardless of the direction of travel thereof.

-Other' objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims. In the accompanying drawings:

Figs. 1 and 2, placed end to end illustrate a conveyor comprising my invention;

Fig. 3 .is a transverse sectional elevational view taken on the line 3-3 of Fig. 1 and showing the .20 belt centering device comprising my invention;

Fig. 4 is a plan view of the belt centeringdeviceof Fig. '3 with the belt omitted;

Fig. 5 is an end elevational view of the belt centering device of Figs. 3 and 4; and

Fig. 6 is a sectional elevational view taken on the line 6--Bof Fig. 3 looking in the direction of the,arrows. I

Referring particularly to Figs. 1 and 2 of the drawings there is seen a trough type of belt con- I 1 veyor particularly adapted for use in mines, such as coal mines, comprising a main frame formed by interconnected head section II], tail section II and removable intermediate sections I2. The

head section I'D isprovided with a head pulley l3 s and apairof tandem drive pulleys M which are driven from a reversible type of electric motor 15 through a speed reducer l6. is'provided with a tail pulley ll.

1 Extending continuously through the main frame of the conveyor and between the head pulley ;I3 and tail pulley I1, and reeved about the mode of operation will be to drive said belt toward the head pulley l3. Special conditions frequent- 1y arise, however, particularlyin a coal mine,

where it is desirable to reverse the direction of travel of the belt I8.

It has been found in practicethat due to the irregular surfaces which mine conveyors rest upon, it is necessary-to :provide v some belt align- The tail section ing or belt centering device to prevent undue wear on the-belt 18.; I In general, howeven-these device'sarenotadapted to function upon a reversal of the normal direction oftravei of the belt,

out only function properly when the belt is driven *5 in a single direction. The belt centering device suitable intervals along the conveyor, asillustrated in Figs. 1 and 2 ,an d are designated generallyv by the reference character 19. Each of said belt centering devices comprises a pairjof 'spaced side'plates ZllfZll having feet 2|, 2i and ?I5 interconnected by a rigidly attachedtransversely extending inverted channel 22 *provided with wings 23, 23 adapted tosupport spill plates 24 which prevent any materialwhich might fall off the upper run of the belt l8 falling on the up- =20 per surface of the lower run thereof.

One of the plates 20 is :provided with an aperture and the-other with a bayonet slot 25, which aperture andbayonet slot receive, respectively, the opposite ends of'theshaft '26 of idler roller 3 5 ill which supports'the lower run of the belt, l8.

It-will be-understood that the belt centering devices l9 form an integral partof the complete conveyor by virtue of their connection to the lon gitudinally extending angle members 28, 28 which 30 form a part of the main frame of said conveyor.

"Said angle members28, 28 are removably at .tached'to'the belt centering devices'l9 by appropriate nuts and bolts'29, 29.

Pivotally mounted upon'the inverted channel 3'5 -22 is an idler-rollersupporting frame 30 which carries apair of inclinedidler rollers 3|, 3| removably mounted thereupon by outer end brackets 32 and 'innerendbrackets 33. The outer end brackets 32 are aperturedtoreceivethe shafts 34 40 of the idler rollers 3| and the inner end brackets 33 are slotted to receive flattened portions of said shafts 34 in a manner well understood in this art. Extending downwardly from the inclined end portions of'the roller supporting frame 30 is a "4 pair. of spaced counterweights 35"which counterbalance the supporting frame 313V and all the elements rigidly attached thereto, about a horizontal axis which passes throughthe pivotal axis thereof afforded by'pivot bolts 36, 3B pivotally mountedupon brackets 31, 31 extending upward ].y from the channel 22. Also supported by the channel-'22 and rigidly-attached thereto, is a cenfltral idler roller-681 mounted-- upon 'angularly 755 formed end brackets 39, 39 which are welded rigidly to said channel 22.

From the above description it will be evident that the idler roller supporting frame 38 is pivoted for free pivotal or swinging movement about a horizontal axis passing through the bolts 36, 35. This axis also passes substantially through the center of gravity of said supporting frame til and the frame about the axis of bolts 38, 36 will notproduce any appreciable lateral movement of the lower ends of the rollers 3i, 3| but will produce lateral movement of the upper ends of said rollers. This is clearly seen by reference to the dotted lines illustrating the movement of the rollers 3|, 3i in Fig. 5 of the drawings.

As clearly illustrated in Fig. 6 of the drawings, the supporting frame 3% is placed near the channel 22 and near the brackets 39. As a consequence, the pivotal. movement of said supporting frame 39 is restricted in both a clockwise and a counterclockwise direction as it will strike the channel 22 or the bracket 39 after movement through a few degrees. In practice I have made the maximum. allowable movement approximately .fourdegrees in both a clockwise and counterclockwise direction from a normal upright position which would be determined by a plane passing through the normal axes of rotation of the inclined idler rollers 3i and the axis of the bolts 36.

In the operation of the device comprising my invention, the reversible electric motor l5 will normally be operated to cause the upper run of the belt to progress toward the head pulley l3. The upper run of the belt will be supported by the inclined idler rollers 3i, 3! and the horizontal roller 38 to form a trough. be supported by the flat idler roller 21.

In the travel of the upper run of the belt 18 toward the head pulley it the friction of said belt will rotate the supporting frame 38 about the horizontal axis of the bolts 36 in a counter-clockwise direction through a relatively small. angle, as illustrated in Fig. 5 of the drawings. This will tend to move the upper ends of the inclined idler rollers 3! to the left, as viewed in Figs. 1, 2 and 5, which will operate to maintain the upper run of the belt it properly. centered or in properalignmerit. Thisis due to the fact that the movement of the upper end of each'roller 3i will be greater than the movement of the lower end thereof in the direction of travel of the upper run of belt its As a consequence, the axesof the rollers 3! will form arcuate angles with the normal plane of said rollers 3!. By virtue of this fact there will be a frictional component between each roller 3i and the contacting surface of the belt 68 tending to move said belt it towards the center line positionv Should the belt it become out of alignment it will be evident that there will be a greater contact between said belt and one of the rollers 3 I than between said belt and the other roller 3!. The roller having the greater contact will consequently have the greater frictional force tend- The lower run will ing to center said belt I8 which will, of course, operate to this end. i

In other words when the unit including the supplemental frame 3!! and the parts carried thereby, tilts forward in the direction of the travel of the belt the upper outer ends of the idlers 3|, 3! will be moved through larger arcs than the lower ends and the idlers 3| then tend to eflect movement of the belt toward the center line of the main conveyor frame 20, 23, 28. The inward rolling tendency will be greater for that idler 3| which has the greater rolling contact with the belt it. But when the belt is automatically centered it will be automatically kept so by the tilted frame 36 maintaining the idlers 3|, 3| in their automatic opposing and beltcentering positions. It is important to note that this automatic action is effective for both directions of travel of the belt and whether the main conveyor frame is on up or down grade or on the level, because under these various conditions the travel of the belt in either direction will effect automatic limited tilting of the centering unit relative to the main conveyor frame.

Should the direction of travel of the belt 18 be reversed for any reason, the frame 30 will swing in a clockwise direction and thus will operate through the rollers 53! to maintain the belt I8 in proper alignment during this reverse travel. It is thus obvious that the belt centering device, comprising my invention, is-operative to maintain the belt it in proper alignment regardless of the direction of travel thereof. 1

As before mentioned, due to the counter-balance condition of the frame 3% and the elements carried thereby, it will operate as well on an inclined as on a horizontal floor.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise constructionherein disclosed.

Having thus described and shown an embodimerit of my invention," what I desire to secure by Letters Patent of the United States is: o

1. In a conveyor, the combination with a main frame, of a reversible belt thereon, means for maintaining said belt in alignment during travel in either direction including an idler supporting frame, belt troughing idler means on said supporting frame, means mounting said supporting frame for free but limited pivotal movement on said main frame about a fixed horizontal axis passing below the belt and in both'clockwise and counter-clockwise directions from a plane passing through the normal axis of rotation of the troughing idler means and the pivotal axis, and means for balancing said supporting frame and the elements carried thereby on said horizontal axis.

2. A belt centering device adapted to center a belt for both forward and reverse directions of travel comprising "a frame, trough forming belt supporting idler means, means supporting said idler means on said frame for free pivotal movement on a horizontal axis passing below the lowtiltably mounting said belt centering device on y W I 2,'195 ,19 9j:- 4 said cr Ss I-piecaand an idler-mounted on said able supplemental" frame," counterbalancing cross-piece for rotation on a fixed axis extend ing transversely'of said supporting frame.

4. A two way'belt centering device comprising a main frame a supplemental frame pivoted thereto on a horizontal transverse axis, cxfantering weights on the lower side of said supple-' mental frame, and idlers on' said,supplementalv frame rotatable on upwardlyandflaterally invclined axes;

5. A two-way belt centering device CQmPIlS- ing a main -frame,. a supplemental frame 'pivoted thereto on a horizontal tr'ansverse'axis, counterbalancing weights secured to "the underside ofsaid supplemental frame, and upwardly-and outwardly inclined troughing idlers mountedfon the lateral end portions of said supplemental,

frame and forming with said supplemental frame and said weights a belttroughing unit through whose center of gravity said-horizontal axisqexa tends. f 6. A belt centering devicecomprising a main .frame, of a supplemental frame pivoted thereto ona transverse: axis, counterbalancing weights; secured to said supplemental; frame, and up: wardly and outwardly inclined'jroughingidlers mounted on the lateral end portions of said supplemental frame and forming with the 1 lat-: ter and'said Weights a belt troughing unit through whose center of gravity said transverse axis extends.

idler mounted on said cross-piece for rotation relatively thereto on a fixed horizontal transverse axis, a troughing u-nitrcomprising upwardly and outwardly inclined idlers mounted on a tiltim ain frame. I

Y 4 1 a a @neoted thereto; 7. In a belt conveyor, the combination with a main frame-, of a center idler mounted th'ereon for rotation relatively thereto on afixed horizontal transverse axis, 'a troughingunitfeom-Q prising upwardly and outwardly inclined idlersv mounted on a tiltable supplemental frame to p I move as a unit therewith; and mechanism for tiltably supporting said supplemental frame on I a fixed. horizontal transverse axis adj acentto Ysaid first-named horizontal axis. 8, In a belt conveyor, the'combinationji'w'ith a main frame'having a cross-piece, of a center 1 weightsfor the unit; and mechanism for tiltably supporting the-said unit on a fixed horizontaltransverse axis adjacent and parallel to said first-named horizontal axis with said weightsin the xtent or tilting or said-unit relative to the 91A, an article ofmanufacture,abalanced unitfcompr'ising a frame; troughing idlers mountfedon the end portions of I said frame, Icoun- \terbalancingiweights securedwto said frame, and, means affording pivotal connections of said frame to ,a support with; the axis of pivotal movement of the'ui'iitextending approximately through the center of gravity of the unit." I

10 ."In *a conveyor, th elcombination with a main frameQof a belt supporting ,idler on ahorizontaltransverse axis,,'inclined; be1t troughing idlers, mechanism comprising (a supplemental frame for supporting 'saidinclined'idl'ers adjacent tdsaidfirst-named idler-{mechanism for supporting said supplemental frame on said main frame vfor limited tiltingmovement relatively; thereto on a transverse axis, and counterbalanc i'ngtimeans on saidsulnplementetl frame for extendingsuch transverse axis [approximately through-the center of gravityof the unit comprising'th'e supplementaljframe and the trough- 'ing idlers with-the counterbalancing, meanscon- 1111-111 a conveyor, thecombination'with a main frame, of a continuous belt thereon, means fordriving said belt in" reverse directions, means formaintaining said'belt 'inalignment during ingframe, a; supplemental frame mounted on said supporting frame for'ifree pivotal movement on a horizontalaxis through limited arcs to opposite Sides offi'an upright plane, inclinednbelt supporting idlers on said supplementalfr'ame, means substantiallybalancing said supplemental "reverse movements comprising an idler si'noportframe on its pivotal axis, said horizontal axis a passing slightly below the lowest point of sup port of said-belton said inclined idlers.

" JOHN s. woon, 

